Ventilation systems are commonly found in modern residential, restaurant, and commercial kitchens. Heat, smoke, and fumes are an ordinary byproduct of cooking many foods and must be removed in order to protect the health and comfort of those present in the kitchen and adjacent areas. Ventilation systems provide an effective way to capture excessive heat, smoke, and fumes generated in kitchens and ventilate them to the atmosphere where they pose no threat to health or safety.
A typical ventilation system consists of an exhaust hood positioned over pieces of cooking equipment that are known to produce heat, smoke, or fumes. This exhaust hood is usually connected via ducts to an exhaust fan and in turn to a vent located on the outside of the building housing the kitchen. The exhaust fan is operated in a way to create a flow of air from the exhaust hood to the outside vent. This creates a suction effect at the exhaust hood that captures the air and any airborne contaminants around the hood. Consequently, any heat, smoke, or fumes generated by the cooking equipment will rise up to the overhead exhaust hood where it will be captured by the suction and transported out of the kitchen to the outside vent. There, it will dissipate harmlessly into the atmosphere.
Most ventilation systems must be manually activated and deactivated by the user. In a typical fast-food restaurant, for example, an employee must manually activate the kitchen ventilation system early in the day or before any cooking occurs. The system will then remain active in order to capture any smoke or fumes that may result from cooking. The system must then be manually deactivated periodically, at the end of the day, or after all cooking has ceased. This manual operation of the ventilation system typically results in the system being active at times when ventilation is not actually required. This needlessly wastes energy not only associated with the operation of the ventilation system, but also due to the ventilation of uncontaminated air supplied to the kitchen by a heating and cooling system. By operating when no smoke or fumes are present, the ventilation system will remove other valuable air that was supplied to heat or cool the kitchen and thus cause the heating and cooling system to operate longer than it would have otherwise.